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Electroplating 101: How Metal Plating Works

Author: Evelyn y

Jul. 01, 2024

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Electroplating 101: How Metal Plating Works

Electroplating lets you combine the strength, electrical conductivity, abrasion and corrosion resistance, and appearance of certain metals with different materials that boast their own benefits, such as affordable and/or lightweight metals or plastics.

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In this guide, you&#;ll learn why many engineers, researchers, and artists use electroplating and metal plating in every stage of manufacturing&#;from prototyping to mass production.

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What Is Electroplating?

Electroplating is the process of using electrodeposition to coat an object in a layer of metal(s). Engineers use controlled electrolysis to transfer the desired metal coating from an anode (a part containing the metal that will be used as the plating) to a cathode (the part to be plated).

Diagram of copper electroplating using an electrolyte bath of copper sulfate, sulfuric acid, and chloride ions. (image source)

The anode and cathode are placed in an electrolyte chemical bath and exposed to a continuous electrical charge. Electricity causes negatively charged ions (anions) to move to the anode and positively charged ions (cations) to transfer to the cathode, covering or plating the desired part in an even metal coating. Electroplating takes a substrate material (often a lighter and/or lower-cost material) and encapsulates the substrate in a thin shell of metal, such as nickel or copper.

Electroplating is most commonly applied to other metals, because of the basic requirement that the underlying material (the substrate) is conductive. Although less common, autocatalytic pre-coatings have been developed which produce an ultra-thin conductive interface, allowing a variety of metals - most notably copper and nickel alloys - to be plated onto plastic parts. 

Electroplating vs. Electroforming

Electroplating and electroforming are both performed using electrodeposition. The difference is that electroforming uses a mold that is removed after a part is formed. Electroforming is used to create solid metal pieces, whereas electroplating is used to cover an existing part (which is made of a different material) in metal.

Electroplating Material Options

You can electroplate a single metal onto an object, or a combination of metals. Many manufacturers choose to layer metals, such as copper and nickel, to maximize strength and conductivity. Materials commonly used in electroplating include:

  • Brass
  • Cadmium
  • Chromium
  • Copper
  • Gold
  • Iron
  • Nickel
  • Silver
  • Titanium
  • Zinc

Substrates can be made of almost any material, from stainless steel and other metals to plastics. Artisans have electroplated organic materials, such as flowers, as well as soft fabric ribbons. 

It&#;s important to note that non-conductive substrates such as plastic, wood, or glass must first be made conductive before they can be electroplated. This can be done by coating a non-conductive substrate in a layer of conductive paint or spray.

Electroplating (3D Printed) Plastic Parts

Thanks to scientific advances in materials and plastic manufacturing, lightweight and low cost plastic parts have replaced more expensive metal parts in a wide variety of applications serving various industries, from automobiles to plumbing pipes.

Although plastic boasts an array of advantages over metal, there are many applications where metal still reigns supreme. Try as you might, you&#;ll never get plastic to have the same opulent finish as copper. And while plastic might be more flexible material than the majority of metals, it&#;s not nearly as strong. This is where metal plating comes in.

3D printing offers unique advantages when combined with electroplating. Engineers often choose to 3D print substrates because of additive manufacturing&#;s design freedom. It is often cheaper to electroplate 3D printed parts than to cast, machine, or use other manufacturing methods, especially when it comes to prototyping.

Stereolithography (SLA) 3D printing is ideal for electroplating because it creates 3D printed parts with very smooth or finely textured surfaces that make the transition between the two materials&#;plastics and metals&#;seamless. It also creates watertight parts that won&#;t get damaged when submerged in the chemical bath required during the electroplating process.

From an engineering standpoint, the combination of 3D printing and electroplating offers unique tensile strength options for finished designs. As you can see in the chart above, the combination of these two manufacturing processes bridges the gap in tensile strength between the two material groups.

Metal plating can have a major impact on the mechanical performance of (3D printed) plastic parts. With a structural metal skin and a lightweight plastic core, parts can be produced with surprisingly high flexural strength characteristics.

In addition to improving mechanical behavior, electroplating can be used to protect plastic parts from environmental degradation. In applications where plastic parts are exposed to chemical attack or ultraviolet light, metal plating provides a permanent barrier that can extend the life of your parts from months to years.

When used as an aesthetic treatment, plating offers an easy way to create prototypes that both look and feel like metal. Depending on the plate thickness, electroplated plastic can be thin and light, or add noticeable weight to a part. Thicker electroplated coatings can even be texturized or polished to achieve a variety of metal finishes, from cast aluminum to mirrored chrome. More complex textures can be achieved by 3D printing a textured resin substrate.

Given the potential combinations of 3D printable materials, a variety of plating metals, and plate thickness ratios, it&#;s easy to see how electroplating gives engineers a new field of design options to consider.

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The Benefits of Electroplating

Electroplating offers many benefits, including increased strength, lifespan, and conductivity of parts. Engineers, manufacturers, and artists capitalize on these benefits in a variety of ways.

Engineers often use electroplating to increase the strength and durability of various designs. You can increase the tensile strength of various parts by coating them in metals such as copper and nickel. Place a metallic skin on parts and you can improve their resistance to environmental factors like chemical exposure and UV light for outdoor or corrosive applications.

Artists often use electroplating to preserve natural elements prone to decay, such as leaves, and turn them into more durable works of art. In the medical community, electroplating is used to make medical implants that are corrosion-resistant and can be properly sterilized.

Electroplating is an effective way to add cosmetic metal finishes to customer products, sculptures, figurines, and art pieces. Many manufacturers also choose to electroplate a substrate to create more lightweight parts that are easier and cheaper to move and ship.

Electroplating also offers the benefit of conductivity. Because metals are inherently conductive, electroplating is a great way to increase the conductivity of a part. Antennas, electrical components, and other parts can be electroplated to increase performance.

The Limitations of Electroplating

Though electroplating boasts plenty of benefits, its limitations lie in the complexity and hazardous nature of the process itself. Workers performing electroplating can suffer from hexavalent chromium exposure if they don&#;t take proper precautions. It is essential for workers to have a properly ventilated workspace. The U.S. Department of Labor Occupational Safety and Health Administration has published numerous documents outlining the risks involved in electroplating.

Although it is possible to electroplate resin parts yourself, amateur users may run into difficulty. The main reason is quality and capability. Laminate adhesion strength using DIY electroplating methods is usually lower than what is achieved by a professional plating service. Structural plating, which requires long plate times, multiple baths, and compatibility between metals, is quite difficult to execute reliably. Successful applications of in-house plating are typically simple and small, such as jewelry prototyping, and thin (single layer) RF copper coatings.

Because of the expertise required and the dangers involved, many engineers and designers choose to hire a third-party electroplating manufacturer specializing in this process. Luckily, several companies, such as RePliForm and Sharretts Plating, specialize in custom electroplating projects. Download our white paper for a list of electroplating services by region and job size.

The video above shows how to electroplate with easy-to-acquire tools, such as a cell charger and spare copper pipe. We recommend you wear a mask, gloves, and eye protection while electroplating and only work in a well-ventilated space.

The Many Applications of Electroplating

Numerous industries use electroplating to make everything from engagement rings to electrical antennas. Here are some common examples:

Aerospace

Many airplane components are electroplated to add a &#;sacrificial coating,&#; which increases the lifespan of parts by slowing down corrosion. Because aircraft components are subject to extreme temperature changes and environmental factors, an additional metal layer is added to a metal substrate so that the functionality of a part isn&#;t compromised by normal wear and tear.

Many steel bolts and fasteners designed for the aerospace industry are electroplated in chromium (or, more recently, zinc-nickel, due to changing restrictions).

Art and Home Decor

Type the word &#;electroplated&#; into Etsy, and you&#;ll be presented with a vast array of electroplated home decor and one-of-a-kind keepsakes. Artisans often turn biodegradable items, including flowers, branches, and even bugs, into durable and long-lasting pieces of art with this process. You can employ electroplating to show off and preserve fine details in items that would otherwise quickly decompose.

Electroplating is often used to create art, such as this copper-plated beetle and honeycomb. (image source)

Digital designers sometimes use electroplating to produce sculptures. Designers can 3D print a substrate using a desktop 3D printer and then electroplate the design in copper, silver, gold, or any metal of choice to achieve their desired finish. Combining 3D printing with electroplating in this manner produces pieces that are easier (and cheaper) to manufacture, while still having the same look and finish as a sculpture that is solid cast metal.

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Additional reading:
10 Questions You Should Know about Diamond Dressing Tools

Automotive

Electroplating is very common in the automotive industry. Many major automotive companies use electroplating to create chrome bumpers and other metal parts.

Electroplating can also be used to create custom parts for concept vehicles as well. For example, VW teamed up with Autodesk to create hubcaps for their &#;Type 20&#; concept vehicle. The prototype hubcaps were 3D-printed and then electroplated. 

Restoration companies and vehicle customization businesses also use electroplating to apply nickel, chrome, and other finishes to various car and motorcycle parts.

Jewelry

Electroplating is perhaps most commonly associated with the jewelry industry and precious metals. Jewelry designers and manufacturers rely on this process to enhance the color, durability, and aesthetic appeal of rings, bracelets, pendants, and a wide range of other items.

When you see jewelry that is described as being &#;gold plated&#; or &#;silver plated,&#; there&#;s a high chance the piece you&#;re looking at was electroplated. Combinations of various metals are used to achieve uniquely hued finishes. For example, gold is often combined with copper and silver to create rose gold.

Medical and Dental

Electroplating is used to add resilient exteriors to all sorts of medical and dental elements. Gold plating is often employed to create tooth inlays and aid in various dental procedures. Implanted parts such as replacement joints, screws, and plates are frequently electroplated to make parts more corrosion-resistant and compatible with pre-insertion sterilization. Medical and surgical tools, including forceps and radiological parts, are also commonly electroplated.

Power

Numerous electrical and solar components are electroplated to increase conductivity. Solar cell contacts and various types of antennas are routinely manufactured using electroplating. Wires can be electroplated in silver, nickel, and many other types of metal. Gold plating is often used (in conjunction with other metals) to increase durability. Gold is also frequently used to increase the lifespan of parts because it is conductive, very ductile, and doesn&#;t interact with oxygen.

Prototyping

Producing custom or low-volume metal parts for prototyping can be very costly and time-consuming with traditional manufacturing processes. As a result, engineers often combine electroplating with 3D printing for a low-cost and time-saving solution.

For example, Andreas Osterwalder of the Swiss Federal Institute of Technology in Lausanne (EPFL) has been able to speed up the prototyping process and reduce costs of advanced experimental setups by 3D printing new designs himself on his Formlabs resin 3D printer and working with Galvotec to have those parts electroplated.

Andreas Osterwalder used 3D printing and electroplating to manufacture this beam splitter.

RF and Microwave Products

Antennas need to have electrical conductivity to propagate radio waves. While plastic 3D printed parts don&#;t conduct electricity, they offer almost infinite design freedom and materials with good mechanical and thermal properties. These benefits can be combined with electroplating to achieve the desired conductivity, resulting in a great solution for custom antennas for research and development in the automotive, defense, medicine, and education.

Electroplating plastic parts creates conductive parts that enable high performance RF applications.

Best Practices for Electroplating 3D Printed Parts

Electroplated composites are a means to a wide variety of ends. Because of its versatility, electroplating opens up countless possibilities across different industries. Want to learn more about electroplating 3D printed parts?

Download our white paper to learn how engineers are adding metal to resin 3D prints, and why hybrid metal parts can open doors to a surprising range of applications, including (but not limited to) enduse strength and durability. By the end of the white paper, you will learn new ways to apply electroplating, as well as design considerations and practical tips on using metal electroplating to amplify the performance of your SLA parts.

What is Electroplating & How Does it Work

While electroplating may seem like advanced technology, it is actually a centuries-old process. The very first electroplating experiments occurred in the early 18th century , and the process was officially formalized by Brugnatelli in the first half of the 19th century. After Brugnatelli&#;s experiments, the electroplating process was adopted and developed across Europe. As manufacturing practices advanced over the next two centuries through the Industrial Revolution and two world wars, the electroplating process also evolved to keep up with demand, resulting in the process Sharretts Plating Company uses today.

Electroplating is also known as electrodeposition. As the name suggests, the process involves depositing material using an electric current. This process results in a thin layer of metal being deposited onto the surface of a workpiece called the substrate . Electroplating is primarily used to change the physical properties of an object. This process can be used to give objects increased wear resistance, corrosion protection or aesthetic appeal, as well as increased thickness.

Electroplating is a popular metal finishing and improving process used in a wide range of industries for various applications. Despite the popularity of electroplating, however, very few outside of the industry are familiar with the process, what it is and how it works. If you&#;re considering using electroplating in your next manufacturing process, you need to know how the process works and what material and process options are available to you.

ELECTROPLATING PROCESS

The electroplating process uses an electric current to dissolve metal and deposit it onto a surface. The process works using four primary components:

  • Anode: The anode, or positively charged electrode, in the circuit is the metal that will form the plating.
  • Cathode: The cathode in the electroplating circuit is the part that needs to be plated. It is also called the substrate. This part acts as the negatively charged electrode in the circuit.
  • Solution: The electrodepositing reaction takes place in an electrolytic solution. This solution contains one or more metal salts, usually including copper sulfate, to facilitate the flow of electricity.
  • Power source: Current is added to the circuit using a power source. This power source applies a current to the anode, introducing electricity to the system.

Once the anode and cathode are placed in solution and connected, the power supply supplies a direct current (DC) to the anode. This current causes the metal to oxidize, allowing metal atoms to dissolve in the electrolyte solution as positive ions. The current then causes the metal ions to move to the negatively charged substrate and deposit onto the piece in a thin layer of metal.

As an example, consider the process of plating gold onto metal jewelry. The gold plating metal is the anode in the circuit, while the metal jewelry is the cathode. Both are placed in solution and DC power is supplied to the gold, which dissolves in solution. The dissolved gold atoms then adhere to the surface of the base metal jewelry, creating a gold coating.

While this process is constant, three factors can impact the quality of the plating. These factors are the following:

  • Bath conditions: Both the temperature and the chemical composition of the bath impact how effective the electroplating process is.
  • Part placement: The distance the dissolved metal needs to travel will affect how effectively the substrate is plated, so the placement of the anode relative to the cathode is important.
  • Electrical current: Both the voltage level and the application time of the electrical current plays a role in the efficacy of the electroplating process.

Learn about more factors that affect electroplating.

WHICH METALS ARE USED IN THE ELECTROPLATING PROCESS?

Plating can occur with individual metals or in various combinations (alloys) that can provide additional value to the electroplating process. Some of the most commonly used metals for electroplating include:

  • Copper: Copper is often used for its conductivity and heat resistance. It is also commonly used to improve adhesion between layers of material.
  • Zinc: Zinc is highly corrosion-resistant. Often, zinc is alloyed with other metals to enhance this property. For example, when alloyed with nickel, zinc is particularly resistant to atmospheric corrosion.
  • Tin: This matte, bright metal is highly solderable and corrosion resistant as well as environmentally friendly. It is also inexpensive compared to other metals.
  • Nickel: Nickel offers excellent wear resistance, which can be improved through heat treatment. Its alloys are also very valuable, offering elemental resistance, hardness and conductivity. Electroless nickel plating is also valued for its corrosion resistance, magnetism, low friction and hardness.
  • Gold: This precious metal offers high corrosion, tarnish and wear resistance and is coveted for its conductivity and aesthetic appeal.
  • Silver: Silver is not as corrosion resistant as gold, but it is highly ductile and malleable, has excellent resistance to contact wear and offers excellent aesthetics. It is also an alternative to gold in applications where thermal and electrical conductivity is needed.
  • Palladium: This bright metal is often used instead of gold or platinum for its hardness, corrosion resistance and beautiful finish. When alloyed with nickel, this metal achieves excellent hardness and plating quality.

Price, substrate composition and desired result are key factors when determining the most appropriate electroplating material for your application.

There are several different plating techniques available, each of which can be used in various applications. Some of these types of electroplating are described in more detail below:

  • Barrel plating: Barrel plating is a method used to plate large groups of small parts. In this process, parts are placed inside a barrel filled with an electrolyte solution. The electroplating process proceeds while the barrel is rotated, agitating the parts so that they receive consistently even finishes. Barrel plating is best used on small, durable parts, but offers a cheap, efficient and flexible solution.
  • Rack electroplating: Rack or wiring plating is a good option if you need to plate large groups of parts. In this method, parts are placed on a wire rack, allowing each part to come into physical contact with the electrical power source. Though more expensive, this option is optimal for more delicate parts that cannot undergo barrel plating. It is important to note that rack plating is more difficult for parts that are sensitive to electricity or have an irregular shape.
  • Electroless plating: Electroless plating, also known as autocatalytic plating, uses a similar process as electrodeposition but does not directly apply electricity to the part. Instead, the plating metal is dissolved and deposited using a chemical reaction in place of an electrical one. While this option is useful for parts that are incompatible with electrical currents, it is more costly and less productive than other options.

While these methods accomplish electrodeposition in different ways, they all use the same basic principles.

USES OF ELECTROPLATING

While electroplating is often used to improve the aesthetic appearance of a base material, this technique is used for several other purposes across multiple industries. These uses include the following:

    • Build thickness: Electroplating is often used to build up the thickness of a substrate through the progressive use of thin layers.

  • Protect substrate: Electroplated layers serve as sacrificial metal coatings. This means that when a part is placed in a harmful environment, the plated layer breaks down before the base material, protecting the substrate from damage.
  • Lend surface properties: Electroplating allows substrates to benefit from the properties of the metals they are plated with. For example, some metals protect against corrosion, improve electrical conductivity, reduce friction or prepare a surface for better paint adhesion. Different metals lend different properties.
  • Improve appearance: Of course, electroplating is also commonly used to improve the aesthetic appearance of a substrate. This can mean plating the substrate with an aesthetically pleasing metal or simply applying a layer to improve surface uniformity and quality.

BENEFITS OF ELECTROPLATING

Electroplating offers a range of benefits for components. Some of the specific benefits of electroplating include the following:

    • Protective barrier: Electroplating creates a barrier on the substrate, protecting it against environmental conditions. In some cases, this barrier can protect against corrosion caused by the atmosphere. This property specifically benefits components because the parts last longer in more harsh conditions, meaning that they need less frequent replacement.
    • Enhanced appearance: Exterior pieces are often plated with thin layers of precious metals to make them more lustrous and attractive to look at. This plating lends aesthetic appeal without exorbitant costs, meaning that attractive parts can be sold at lower prices. Additionally, electroplating is often used to prevent tarnishing on silverware, improving longevity and aesthetic appearance over time.
    • Electrical conductivity: Silver and copper plating help improve electrical conductivity in parts, offering a cost-effective, efficient solution for improving conductivity in electronics and electrical components.

  • Heat resistance: Several metals, including gold and zinc-nickel, are resistant to high temperatures, improving the ability of the substrate to resist heat damage. This, in turn, can improve the lifespan of plated parts.
  • Improved hardness: Electroplating is often used to improve the strength and durability of substrate materials, making them less susceptible to damage from stress or rough use. This quality can help increase the lifespan of plated parts, reducing the need for replacement.

Some benefits offered are metal-specific. For example, nickel plating is useful for reducing friction, which helps to reduce wear and tear and improve part longevity. Zinc-nickel alloys, on the other hand, are used to prevent the formation of sharp protrusions during manufacturing, which can result in part damage. Copper is also specifically used as an undercoating in many applications, as it facilitates adhesion with additional metal coatings to improve the surface quality of the final part.

INDUSTRIES THAT USE ELECTROPLATING

Whether your company is looking for corrosion protection, improved durability or increased electrical conductivity, electroplating offers solutions. That&#;s why electroplating is widely used across a variety of industries. Listed below are some of the industries SPC serves and how they apply electroplating:

    • Automotive industry: Plating is commonly used in the automotive industry to prevent corrosion in harsh environmental conditions. Zinc-nickel plating solutions help prevent rust formation, while electroless nickel plating serves as a great alternative for chrome on catalytic converters and plastic parts.
    • Electronics industry: Electronics companies often use gold plating for its conductivity, applying it to semiconductors and connectors. Gold is also coveted for its corrosion resistance in this industry. Copper plating is another commonly used metal in this industry, used as an alternative to gold when the focus is on conductivity. Palladium alloys are also commonly used as protective coatings on electronic equipment and components.

  • Medical industry: The medical equipment industry often uses metal electroplating to improve the biocompatibility of components, especially implants. Gold, silver and titanium are commonly used in this industry for their biocompatibility, corrosion resistance, hardness and wear resistance, all of which are essential for implants and joint replacements.
  • Aerospace industry: The aerospace industry frequently uses titanium for aircraft manufacturing due to its high strength-to-weight ratio. Nickel plating is also commonly used in this industry to protect against corrosion and wear, while copper is used to improve heat resistance.
  • Oil and gas industry: Corrosion protection is a primary concern of the oil and gas industry due to the nature of petrochemicals. Electroless nickel plating is often used in this industry to help protect piping and other components from corrosion, which helps improve the longevity of parts.

Many other industries, including the firearms, military and defense industries, also use electroplating in various applications. All of these industries favor electroplating for its functional capabilities, as well as its low cost and flexibility of application.

ELECTROPLATING EXAMPLES

There are many specific examples of electroplating applications across various industries. Some of these are detailed below:

    • Copper plating of semiconductors: Various metal plating options are used in the electronics industry. Copper plating is commonly used to increase the ability of semiconductors and circuits to conduct electricity.

  • Nickel plating of hard drives: Nickel is a magnetic metal, which is an essential property for hard drives. Hard drives require magnetism to improve disc reading, so hard drives are commonly electroplated with nickel during the manufacturing process.
  • Palladium plating of catalytic converters: Palladium plating is commonly used in the automotive industry, specifically on catalytic converters. Palladium absorbs excess hydrogen during the manufacturing process, an element that negatively impacts the functionality of catalytic converters. Plating with palladium absorbs this excess hydrogen, improving catalytic converter performance.
  • Electroless nickel plating of aerospace components: Black electroless nickel plating is capable of absorbing light and energy. This is an essential quality in the manufacturing of various types of defense vehicles. Many defense and aerospace industry manufacturers choose to use this plating option to ensure compliance with industry standards, including the Department of Defense guidelines.

With our extensive experience in a range of industries, SPC can assist with these electroplating applications and more, offering a range of cost-effective plating services.

CHOOSE SPC

Determining your best manufacturing options is essential for your company&#;s efficiency. Electroplating serves as a functionally and financially beneficial option for a variety of applications, but you need to partner with the right plating company to see all the benefits. There are several factors that influence the results of electroplating. Sharretts Plating Company can help.

SPC has over nine decades of experience in the industry, developing a wide range of cost-effective plating and metal finishing processes to suit the needs of companies across numerous industries. We can help you determine the best plating method for your project, as well as the type of metal you&#;ll want to use. With SPC, you can trust us to provide experienced, customer-focused service from start to finish.

Contact SPC to learn more about the electroplating process and how it could benefit your business and request a free quote now!

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